SIGNAL TRANSDUCTION - PowerPoint PPT Presentation

SIGNAL TRANSDUCTION. DR AMINA TARIQ BIOCHEMISTRY. Cell-Cell Interactions . For a coordinated function of cells in a tissue, tissues in an organ, organs in a system and systems in the body, cells need to be able to communicate with each other.

Copyright Complaint Adult Content Flag as Inappropriate

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

Download Presentation

PowerPoint Slideshow about 'SIGNAL TRANSDUCTION' - morgan

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

is a way for a cell to alter its own extracellular environment, which in turn affects the way the cell functions. The cell secretes chemicals outside of its membrane and the presence of those chemicals on the outside modifies the behavior of that same cell. This process is important for growth.

is a transfer of ions or small molecules from one cell to its neighbor through pores in the membrane. Those pores are built out of membrane proteins and are called gap junctions. This is the fastest mode of cell-cell communication and is found in places where extremely fast and well-coordinated activity of cells in needed. An example of this process can be found in the heart. The muscle cells in the heart communicate with each other via gap junctions which allows all heart cells to contract almost simultaneously.

Thus the gene begins to be transcribed and translated, and a new protein appears in the cell and assumes its normal function within it (or gets secreted).

The action of nuclear receptors is slow, as it takes some hours for the whole process to occur. The effect is long-lasting (or even permanent) and changes the properties of the cell. This type of process is important in development, differentiation and maturation of cells, e.g. gametes (eggs and sperm cells).

When a signaling molecule binds to an ion channel on the outside of the cell, this triggers the change of the 3D conformation of the protein and the channel opens, allowing the ions to move in or out of the cell following their electrical gradients and thus altering the polarization of the cell membrane. Some ion channels respond to non-chemical stimuli in the same way, including changes in electrical charge or mechanical disturbance of the membrane.

When a signaling chemical binds to the membrane receptor protein on the outside of the cell, this triggers a change in the 3D conformation of that protein, which in turn, triggers a chemical reaction on the inside of the cell.

Transmembrane proteins include G protein-linked receptors and they are seven-pass trans membrane proteins. This means that the polypeptide chain traverses the membrane seven times. When a chemical - a hormone or a pharmaceutical agent - binds to the receptor on the outside of the cell, this triggers a series of chemical reactions:

estrogens and gonadotropins are used in treatment of sterility and menstrual disturbances.

Huggins received the Nobel Prize in 1966 for the introduction of a new form of cancer therapy in which sex hormones are used to retard their growth. He used androgens for breast cancer and estrogens for prostate cancer.